1. Field of the Invention
The apparatus and method of the present invention relate generally to the field of unclogging clogged sewer systems and, more particularly, to unclogging surcharged sewage manholes. More particularly, this invention relates to a method and apparatus used to break down and dissipate surcharge waste material clogging manholes.
2. Description of the Prior Art
Sewer systems include sewer pipes and manholes. In the context of the present invention, sewer pipes typically include six inch diameter pipes that transport liquid and solid waste materials from residential, commercial, industrial and other waste producers. The sewer pipes are typically placed underground. Sewer pipes are known to become clogged from the infiltration of sand, greasy materials, sticks, stones, tree roots, and the buildup of other materials settling out of the waste stream.
Manholes are typically 23 inch diameter pipes that extend from ground level down to the sewer pipes and provide access to the sewer pipes, including access to unclog the sewer pipes when the sewer pipes become clogged. The manholes are typically spaced at 350 foot intervals along the sewer pipes. When a sewer pipe becomes clogged, the liquid and solid waste materials in the sewer pipe fill the sewer pipe upstream of the clogged location, and, as the sewer pipe becomes filled, the liquid and solid waste materials rise in manholes upstream of the clogged location in the sewer pipe. Furthermore, when a sewer pipe becomes clogged, resulting in liquid and solid waste rising into a manhole, the liquid and solid waste in a manhole can thicken and solidify, thereby forming a plug in the manhole. The waste material filling a manhole is know as surcharge.
It is known that when a clogged sewer pipe results in one or more manholes becoming surcharged, the surcharge in the manholes must be liquefied before the sewer pipe is unclogged. This allows the waste materials in the surcharged manholes to flow unimpeded through the sewer pipe when the sewer pipe is unclogged. If surcharged manholes were unclogged after the sewer pipe is unclogged, then, when the waste materials in the manholes are broken down, chunks in the clogged manhole could fall into the sewer pipe and re-clog the sewer pipe.
It is normally best to unclog a clogged sewer pipe from the first dry manhole downstream of the clogging obstruction. This allows a clear manhole from which to work and uses the flushing effect of the waste-water flow to clear the pipe. However, roots infiltrating sewer pipes tend to grow in a downstream direction. When roots are suspected as the major cause of a clogged sewer pipe, there can be an advantage to unclogging the sewer pipe from an upstream manhole because the large tap root can be more easily reached from the upstream side, eliminating the necessity of working through all the fine feeder roots. This situation also necessitates the dissipation of the surcharge in upstream manholes before unclogging the sewer pipe. After the surcharge is dissipated, the surcharge is removed from the manhole by means such as pumping or suction, thereby allowing access to unclog the clogged sewer pipe.
It is known in the prior art to provide devices of various designs to clean and unclog sewer pipes. Such devices include a device mounted on skids and pushed through the sewer using a hydraulic motor, using high pressure water for rotating and cutting to clean the sewer pipe. This is disclosed in U.S. Pat. No. 4,766,631, entitled "Sewer Pipeline Hydraulic Root Cutter Apparatus" that issued Aug. 30, 1988 on an application filed Sep. 1, 1987 in the name of Patrick R. Crane and Donald J. Bell, and U.S. Pat. No. 4,516,286, entitled "Sewer Pipeline Cleaning Apparatus" that issued May 14, 1985 on an application filed Jun. 6, 1983 in the name of Patrick Crane. It is also known to provide rotating brushes or cutters driven by an electric motor for moving through a pipe for cleaning. This is disclosed in U.S. Pat. No. 4,773,115, entitled "Sewer Cleaning Device" that issued Sep. 27, 1988 on an application filed Oct. 7, 1986 in the name of Robert C. Smith. It is also known to provide a small electric motor mounting a grapple hook, cutter, or cleaner, with the electric motor pushed through the sewer by a rod, snake or flat bar tape. This is disclosed in U.S. Pat. No. 5,226,207, entitled "Sewer Unclogger" that issued Jul. 13, 1993 on an application filed Dec. 20, 1991 in the name of William Elzaurdia. It is also known to provide a small pneumatically driven motor mounting a grapple hook, cutter, or cleaner, with the pneumatically driven motor pushed through the sewer by a rod, snake or flat bar tape. This is also disclosed in U.S. Pat. No. 5,226,207. It is also known to provide a grapple hook or cutter or other tool connected to a distal or leading end of a snake or rod wherein the snake or rod is connected to a rotation source outside of the pipe. It is also known to provide a bullet-shaped cleaning head with rearward facing water jet nozzles. Water under high pressure, such as 2000 pounds per square inch (psi), exits the rearward facing nozzles to propel the cleaning head forward to break up obstructions in the sewer pipe. The high pressure water spray out of the rearward facing nozzles also serves to wash solid material from the walls of the sewer pipe. This is illustrated in several method and apparatus patents granted on applications filed in the names of Sheron R. Sheppard and Henry B. Polston. These patents include: U.S. Pat. No. 5,341,539, entitled "Apparatus for Cleaning Waste Collection System" that issued Aug. 30, 1994 on an application filed Dec. 2, 1991; U.S. Pat. No. 5,336,333, entitled "Method for Cleaning Waste Collection Systems" that issued Aug. 9, 1994 on an application filed Dec. 2, 1991; U.S. Pat. No. 5,129,957, entitled "Method for Cleaning Sewers" that issued Jul. 14, 1992 on an application filed Aug. 19, 1991; and U.S. Pat. No. 5,068,940, entitled "Apparatus for Cleaning Sewers" that issued Dec. 3, 1991 on an application filed Nov. 1, 1990.
Presently, a surcharge in a clogged manhole is liquefied by adding a large amount of water, e.g., 800 to 1000 gallons, to the solidified sewage while agitating the water-sewage mixture with a rod or pole. This process of manually stirring a manhole's surcharge usually takes 45 minutes per manhole, and the sewage in all surcharged manholes must be liquefied before clearing the sewer line blockage. After the sewage in all surcharged manholes has been liquefied, the sewer pipe is unclogged using a device such as one of the sewer pipe cleaning and unclogging devices listed above.